SpaceX Launches NASA Satellite To Search For Alien Worlds

Updated at 8:40 p.m. ET

SpaceX has launched NASA's planet-hunting satellite TESS into outer space Wednesday evening from Cape Canaveral.

Tess — short for Transiting Exoplanet Survey Satellite — will spend two years searching for planets near bright, nearby stars. The satellite was launched on a SpaceX Falcon 9 rocket.

The launch window was narrow — just 30 seconds — and TESS was to be deployed into orbit about 48 minutes after launch.

"Following stage separation, SpaceX will attempt to land Falcon 9's first stage on the 'Of Course I Still Love You' droneship, which will be stationed in the Atlantic Ocean," SpaceX says.

The launch of TESS was originally scheduled for Monday, but SpaceX pushed it back two days to conduct more analysis of guidance, navigation and control systems.

NPR's Nell Greenfieldboyce reports that TESS will scan nearly the entire sky for alien worlds. The satellite will build on work of the Kepler mission, which found more than 3,000 planets around far-off stars:

"MIT astronomer George Ricker, the principal investigator for TESS ... says the challenge with the Kepler discoveries is that the planets' host stars are far too faint to allow detailed follow-up measurements. 'We know that planets in principle exist there," says Ricker, "but there's really not much more we can say other than that they exist.'

"The planets discovered by TESS will be different, as TESS will search for planets around closer, brighter stars. ...

"The ultimate goal is to find small, probably rocky planets orbiting in a sweet spot around stars that's not too hot, and not too cold. Those planets could be studied using the James Webb Space Telescope that NASA is supposed to launch in a couple of years. Researchers would be able to use it to analyze the starlight that filters through the planets' atmospheres, looking for hints of habitability."

Researchers expect that TESS will find around 20,000 planets to target for future study, Nell says.

"If all goes well with the launch and calibration phases of the mission, the first haul of new planets found by TESS could be announced later this year," Nell reports.

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